Rubber-metal mounts of this type have been disclosed in German Offenlegungsschrift DE-OS No. 23 28 566 (see especially FIGS. 1A and 1B of that patent), and means are already proposed therein whereby rubber-metal mounts of this type are modified in such a manner that in one direction i.e., in the direction of the axial center line, the mounts are relatively stiff, whereas in the other direction, i.e., transversely thereof, they are relatively soft. This problem is particularly significant in conjunction with the suspension, on at least three points, of internal combustion engines in motor vehicles. Since there will occur variances during the actual production from the theoretical design, it is difficult to prevent, even with a three-point engine suspension, the rubber-metal mounts from being subjected to preloading. This is because the suspension point locations on the body, due to production inaccuracies, do not always correspond exactly with those on the engine to ensure proper alignment. In a three-point suspension of this type, two of the suspension points can be readily equipped with rubber-metal mounts, as long as the third suspension point is not being used, because two points can always be connected by a straight line. However, if a rubber-metal mount is used on the third suspension point, one will encounter the distortion problem outlined in the foregoing. One must realize that a distorted or twisted rubber-metal mount cannot provide the type of acoustic damping for which it was originally designed and, as a result, the interior noise level, i.e., the acoustic comfort inside the vehicle, may be adversely affected. In an effort to render the rubber-metal mount of the third suspension point relatively soft with respect to its axial center line of mounting, it is proposed in the above-mentioned German DE-OS No. 23 28 566 that a recess be provided in the rubber member, so that there is some play between the metal fastening elements of the rubber-metal mount that will allow relative displacement. However, this arrangement is still afflicted with the disadvantage that the rubber-metal mount is subjected to preloading so that the problem identified above is not eliminated.
In the German Offenlegungsschrift DE-OS No. 23 13 431 it is proposed that the rubber member be reinforced in the direction of its axial center line by metal rings which are embedded in the rubber member and which extend transversely of the axial center line. However, even in this arrangement the rubber-metal mount will be subject to distortion when the fastening element of the rubber-metal mount is displaced from its axial center line. So this proposal, too, cannot be considered a satisfactory solution.